In a recent announcement, it has been confirmed Sonic (and a few other SEGA character such as NIGHTS and Tails) will appear in the new and upcoming SEGA PC title, SEGA Splash Golf.
Sonic appears in the game as the caddy, he gets your balls, supports you along, and much more. Besides the fact Sonic and Tails are in the game, there’s also golf courses based around Sonic, such as the Green Hill Zone. Other SEGA characters to appear include NIGHTS, the puyo pop clan, Opa Opa, and Ulalala.
The game is coming out later this year to the PC, unfortunately there is no confirmation of a US or Europe release. Sonic Stadium will keep you updated on news of this game.